Stripper bar mounting for rock breaker



Feb. 25, 1958 A. B. HANSE ET AL 0 STRIPPER BAR MOUNTING FOR ROCK BREAKER Original Filed Dec. 18, 1950 3 Sheets-Sheet 1 Qlfieri l3 Hanak flh l INVENTORS.

Feb. 25, 1958 l A, B, HANSE r A 2,824,704

STRIPPER BAR MOUNTING FOR ROCK BREAKER Original Filed Dec. 18, 1950 3 Sheets-Sheet 2 o o o 0 o o o F k\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\$ :2 INVENT R5. 43 'CZZberZZZB. 07256. 44 By Fred 120115726.

.Feb. 25, 1958 I r A. B. HANSE ETAL 2,824,704

STRIPPER BAR MOUNTING FOR ROCK BREAKER Original Filed Dec. 18, 1950 Q 3 Sheets-Sheet 3 DEAD CENTER INVENTORS. CZZberi-Efihnae, BY Fred 2,824,704 sTRIPPER BAR MOUNTING FOR ROCK BREAKER Albert E. Hanse, Cedar Rapids, Iowa, and Fred W. Rollins, Danville, Pa., assignors to Pettibone Mulliken Corporation, Chicago, 111., a corporation of Delaware United 6 Claims. (Cl. 241-286) In breaking up large rocks, it has long been recognized that one of the most eflicient methods of breaking the rocks comprises impact breaking. Typically, the large rock is dropped into the path of a rotating hammer, which strikes the rock with sufficient speed to shatter it. A number of different impact breakers have been provided. Nevertheless, impact breakers have not, prior to the present invention, reached the potential attainable with this invention. Our invention, first disclosed in our application Ser. No. 201,364, filed December 18, 1950 (now Patent 2,767,928 of October 23, 1956), provides various improvements for increasing the efficiency and effectiveness of impact breakers and. in some respects, is suitable for use with other breakers as well.

One important feature of the invention, which is particularly the subject of this divisional application, relates to the mounting of the stripper bar. This is a bar which isnormally stationary and is positioned fairly close to the circle of movement of the hammers so as to prevent the passage of oversized pieces through the machine. It is desirable that such stripper bars be yieldable, in order to prevent expensive breakage of the machine in case a large piece of tramp iron or other excessively tough material should be fed to the machine with the rock.

Heretofore, many of the stripper or breaker bars which have been yieldably mounted have been mounted in such away that they would yield more readily when struck near the ends than when struck near their center. This made optimum adjustment diflicult, because an adjustment of yieldability such that the stripper bar would yield to center-striking objects with safety was likely to cause it to yield undesirably readily to objects striking the ends of the stripper bar. Any adjustment would be likely either to fail to fully protect the machine, or to permit passage of large pieces of rock which should have been retained until broken. Furthermore, stripper bars of the past were in some instances likely to shear off parts when they were forced out by tramp iron, with necessity for delay while the parts were replaced, even if they were shear pins or the like which could be replaced relatively inexpensively and quickly. According to the present invention, a uniform resistance to movement is provided throughout the length of the stripper bar and, after yielding, it is instantly and automatically restored to its original position without danger that parts will be broken. An important part of the mounting comprises spaced pairs of toggle levers, of which one member of each pair is coupled to a rotatable sleeve so that the two pairs must act in unison, thereby restricting the movement of the stripper bar to one in which both ends move uniformly. The toggle linkage also facilitates the desired degree of firmness in the stripper bar while letting it move relatively freely, once its movement has begun. In addition, an improved spring system has been devised for loading the toggle linkage to provide the desired resistance of movement to the stripper bar.

Additional objects an advantages will be apparent from the following description and from the drawings.

tes Patent (3 "ice 2 DESIGNATION OF FIGURES Figure 1 is a perspective view of a rock breaker built in accordance with the present invention and which has been chosen for illustration thereof.

Figure 2 is a longitudinal, vertical, cross-sectional view taken, for the most part, approximately through the middle of the structure of Figure 1.

Figure 3 is a fragmentary,approximately vertical, sectional view, taken near the line 33 of Figure 2 and showing particularly the face of the main deflector screen grate.

Figure 4 is a fragmentary view on a larger scale, showing the wedging features for holding a hammer in place.

Figure 5 is a sectional view taken approximately on the line 55 of Figure 2, showing particularly the construction and mounting of the stripper bar and its tensioning means.

Figure 6 is a fragmentary side view of the structure shown in Figure 5, being taken approximately on the line 66 of Figure 5, the parts being shown slightly tilted in a clockwise direction, so that the parts may be positioned as projections of like parts in Figure 5, for greater clarity.

Figure 7 is a face view of the lower grating.

Although the law requires setting forth the preferred form of the invention and the inclusion of a full and exact description of at least one form of the invention, such as that which follows, it is, of course, the purpose of a patent to cover each new inventive concept therein no matter how it may later be disguised by variations in form or additions of further improvements; and the appended claims are intended to accomplish this purpose by particularly pointing out the parts, improvements, or combinations in which the inventive concepts are found.

GENERAL OPERATION The form of the invention chosen for illustration is seen generally in Fig. l. The internal structure is seen generally in Fig. 2. Large rocks are fed to inclined slide 11 and slide from this slide into the circle of rotation of a rotary hammer assembly 12. Here the rock is struck by one of the hammers 13, which shatters or fractures the rock and throws the pieces toward grid 14, composed mainly of spaced bars 16 in vertical planes. Most of the pieces which are small enough pass through the grid 14 and fall through the discharge area 17. Usually a conveyor is provided below the illustrated apparatus to receive the broken rock and carry it to a vibratory screen. The larger pieces of fractured rock will strike the bars 16 and usually be deflected upwardly and inwardly to drop clear of grid 14 and be struck by the hammers, sometimes being broken by this impact. The bars 16 preferably have faces flat transversely and curved longitudinaly, as shown, about a point a little above the zone of impact of fresh rock with rotary hammer. Accordingly, many of the rock fragments will ricochet upwardly and rearwardly, so that they will drop back into one of the hammer circles of hammers 13 and 20 at a suflicient speed so that many fragments will be struck by the faces of hammers 13 instead of their corners. Particles are blocked from flying out of the breaker by curtains formed of chains 18. Flying dust may be reduced by one or grid 14 will fall onto a second rotary hammer 20, which. will again shatter it, most of the pieces flying against or through grid 14.

Stripper bar A stripper bar 66 (an assembly of parts) is positioned as seenbest in Fig. 1 to lie close to the hammer circle of the rotary hammer 20. This stripper bar is carried in a stripper bar guide 67, which forms an opening through the side plates 44. The-stripper bar assembly, at both ends, extends through the side plates. It is shiftable in guides67 to move toward or away from the-hammer circle, the position control being described under the next heading. The form of stripper bar illustrated is best understood from Fig. 5. From this, his seen that the stripper bar comprises two main parts, namely, a head 68 and a carrier 69, which latter extends through the guides 67 and side walls 44. The head 68 is provided with tongues 71, into which draw bolts 72 are dropped through an open-sided slot. The head and bolt assemblyis then slipped into carrier 69 and drawn tight by nuts 73, which may rest on washers or an apertured plate 74. A carrier 69 may have guide lugs 76 welded thereto. QA wear plate 77 (Fig. 2) may be applied to theexposed faceof the carrier 69, having been omitted from Fig. 5, partly for clarity and partly because it is not deemed necessary, at least unless the rock is very abrasive.

Stripper positioning and control The position of the stripper bar assembly 66 is-determined with reference to a torque tube 78,-which-is'pivotally carried by plates 79 secured toside plates. ':The torque tube is urged by spring bars 81 in the direction of the arrow shown in Fig. 6 to turn plates '82' thereon in a direction to thrust stripper bar 66 forwardly, namely, to the left, as seen in Figs. 5 and 6. The plates 82-1are welded to torque tube 78 and comprise'links of a pair of toggle link systems. Thus each plate or lii1k82-ei1 gages a link assembly 83, which engages a pin=84 extending outwardly from the end of carrier -69. It'is apparent from Fig. 6 that as the plate 82 is turned-counterclockwise toward its illustrated position, they-toggle linkage comprising link 83 and plate 82 approaches alignment and the stripper bar 66 is thrust forwardly. The stripper bar is preferably placed firmly againsta stop, such as shims 86, which.may be inserted. or removedfin accordance with the desired position of the stripper bar 66. The shims 86 may be of T-shape, with the legs fitting into the slot formed by guide 67 and with the heads provided with an aperture through which a bolt 87 may, pass to hold the shims in place.

The length of the toggle link 83 is preferably adjustable. This adjustment may be accomplished by wedges, but in the illustrated form it is accomplished by bolts 88. When these bolts are tightened, they clarnplink plates .89 against link plate 91. Link plate 91 engages apin 84, while link plate 89 engages plate or linkf82, being pivoted thereto by a bolt 90.

The length of link 83 is adjusted to .keep the,,toggle linkage slightly out of 'deadcenter alignment when the stripper bar 66 is thrust home. As a further safeguard to prevent the toggle linkage from swinging ,into alignment, an adjustable stop'92 is provided. This stopl'may be mounted on side plates 44 and adjusted by' a screw 93, bolts 94 being tightened when it is properly, positioned. F

The spring bars 81 are anchored atone end to a torque ring 96 which may be secured to tube 78 bylbolts' f97. At their other ends, the spring bars 81 areanchoredin a torque ring 98, which is held within tube-781by bolts 99. In this instance, however,the bolts199 ride in .anannular. groove 101 in torque ring 98, so that it may,.t1irn with respect to tube 78. Asfseen best inFig. 1, a tensioning lever 102 is secured totorque ring 98 so as .toturnlthis torque ring and twist .the spring, rods .81. .The. tensioning lever 102 is held in its. tensioned position by a. link 103 secured to the side platev 44. In making any. adjustment; the bolt "104 securing lever 102 'to;.link,,103 is first removed and the lever 102 eased to its natural po' sition to relieve the tensionzon the parts.

. The tension can be varied by changing the number of spring bars 81. These are anchored to the torque rings 96 and 98, as seen in the cross section of ring 96 in Fig. 5. The center aperture in ring 96 is squared in cross section. In the illustrated form, it is large enough to hold 16 of the bars 81 arranged in four rows of four each. It may be assumed, however, that only four of bars 81,are illustrated, the space of the remaining twelve being occupied by filler pieces 106.

The force required for a piece of tramp iron or the like to press the stripper bar 66 outwardly depends on the number of spring bars 81 used and also on the proximity of the toggle links 82 and 83 to alignment. Hence, minorvariations in the seating force applied to stripper bar 66 may be made by adjusting the length of composite links 83, the position of stop 92 preferably being changed accordingly. It is usual, however, for the stop 92 to be slightly spaced below the toggle link 83 so as to ensure firm seating of the stripper bar 66 on the shims 86.

As the toggle linkage collapses, its mechanical advantage decreasesrapidly, more than ofisetting the increasing spring tension, at least in the initial part of the stroke which is all that usually occurs. It is desirable for the stripper bar to move back relatively easily once it has started, and it is especially desirable for it not to increase its opposition to movement, as this would necessitate setting the initial tensionlower than the optimum or would fail to'give the degree of protection desired.

To limitthe outward movement of the stripper bar, one or more stops 108 maybe provided, these stops preferablyfb'eing adjustable to permit as much movement as is safe. They should protect spring bars 81 against being twistedfar enough to acquire a set. v

.A seal plate 109 ispreferably provided in conjunction withthe stripper bar to seal the opening in guide 67 against the .passage of flying dust therethrough. The plate 109may be. secured to the stripper .bar carrier 69 and may slide in guideways 111.

The discharge passage behind grid 14, stripper bar 66 and grating 112 is preferably wide and unobstructed, as shown. The various demarcations shown therein in Fig. 2 are all as shallow as the thickness of liner plates 48, so that even clay is not likely to accumulate and clog.

As stripper head 68 wears, it may be turned over for longer life.

Other features of the invention are fully described in the parent application Ser. No. 201,364, and the disclosure thereof whereby incorporated herein by reference.

We claim:

1. A rock breaker including a rotary hammer for breaking rock fed to the hammer, a stripper bar normally stationary close, to the circle of movement of the hammer, and means for yieldably holding the stripper bar in that position including means engaging the stripper bar adjacent its ends at opposite sides of the breaker and restricting each end of the stripper bar to movement matched by; movement of the other end of the stripper bar, namely, two pairs of toggle links, of which a first link ,of each pair is'attached at one end to the stripper bar and at the other end to the second link of the pair, a rotatablymounted, member to which each of the other links is firmlysecured to rotate about a common axis, spring means for urging said rotary member in a direction to thrust the stripper bar to said position by moving the pairs of toggle links toward alignment, and means for restricting the movement of the parts to bring the stripper bar to rest before the toggle links reach align ment.

2. A rock breaker including a rotary hammer for breaking rock fed tothe hammer, a stripper bar normally stationary close to the circleof movement of the hammer, and means for yieldably holding the stripper bar in .thatposition including means engaging the stripper bar adjacent its ends at opposite sides of the breaker and restricting each end of the stripper bar to movement matched byrnovement of'the other end of the stripper bar, namely, two pairs of toggle links, of which a first link of each pair is attached at one end to the stripper bar and at the other end to the second link of the pair, a rotatably-mounted member to which each of the other links is firmly secured to rotate about a common axis, spring means for urging said rotary member in a direction to thrust the stripper bar to said position by moving the pairs of toggle links toward alignment, and means for restricting the movement of the parts to bring the stripper bar to rest before the toggle links reach alignment, including a seat against which said stripper is pressed.

3. A rock breaker including a rotary hammer for breaking rock fed to the hammer, a stripper bar normally stationary close to the circle of movement of the hammer, and means for yieldably holding the stripper bar in that position including means engaging the stripper bar adjacent its ends at opposite sides of the breaker and restricting each end of the stripper bar to movement matched by movement of the other end of the stripper bar, namely, two pairs of toggle links, of which a first link of each pair is attached at one end to the stripper bar and at the other end to the second link of the pair, a rotatably-mounted member to which each of the other links is firmly secured to rotate about a common axis, spring means for urging said rotary member in a direction to thrust the stripper bar to said position by moving the pairs of toggle links toward alignment, and means for restricting the movement of the parts to bring the stripper bar to rest slightly before the toggle links reach alignment.

4. A rock breaker including a rotary hammer for breaking rock fed to the hammer, a stripper bar normally stationary close to the circle of movement of the hammer, and means for yieldably holding the stripper bar in that position including two pairs of toggle links, of which the first links of each pair are attached at one end of each to opposite ends of the stripper bar and at the other end of each to the second link of the pair, a rotatably-mounted tube on which said second links are secured, a plurality of bars of spring steel extending through said tube, and anchored to the tube at one end, a torison plate to which the other ends of the bars are anchored, and means for twisting said torsion plate to load said spring bars.

5. A rock breaker including a driven rock-breaking member, an opposing member against which rock may be crushed by the driven member and means for yieldably holding the opposing member including two pairs of toggle links with the first link of each pair connecting opposite ends of the opposing member to the secand links respectively, a rotatably-mounted tube on which said second links are secured, a plurality of bars of spring steel extending through said tube, and anchored to the tube at one end, a torsion plate to which the other ends of the bars are anchored, and means for twisting said torsion plate to load said spring bars.

6. A rock breaker including a driven rock-breaking member, an opposing member against which rock may be crushed by the driven member and means for yieldably holding the opposing member including two pairs of toggle links with the first link of each pair independent of the other first link and these first links connecting opposite ends of the opposing member to the second links respectively, a rotatably-mounted member to which each of the second links is firmly secured to rotate about a common axis, spring means for urging said rotary member in a direction to thrust the opposing member to its normal position by moving the pairs of toggle links toward alignment, and means for restricting the movement of the parts to bring the stripper bar to rest slightly before the toggle links reach alignment.

References Cited in the file of this patent UNITED STATES PATENTS 198,561 Blake Dec. 25, 1877 702,889 Steckel June 17, 1902 740,215 Bartholow Sept. 29, 1903 1,125,137 Liggett Jan. 19, 1915 2,375,370 Krider May 8, 1945 2,597,635 Grisdale May 20, 1952 

